Method of and apparatus for rolling tubes from alpha hollow block



June 24, 1930.- MLROECKNER 1,767,896

METHOD, OF AND APPARATUS FOR ROLLING TUBES FRO! A HOLLOW BLOGK Filed Feb. 6, 1928 fizolalfarm) Patented June 24, 1930 UNITED, STATES PATENT OFFICE VEREINIGTE STAHLWERKE AKTIENGESELLSC'HAFT, OF D'USSELDORF, GERMANY METHOD OF AND APPARATUS FOR ROLLING TUBES FROM A HOLLOW BLOCK- Application filed February 6, 192a, scrial No.

. It is known, for instance by my prior U. S. Patent .No. 1,610,593, to make tubes from a hollow block by subjecting the latter to the action of a system of pans of rolls arranged about the hollow block at a certain distance from its axis, each pair of rolls acting with one roll from inside and with the other roll from outside said block upon the walls of the latter. The pairs of rolls are of gradually increasing width and of adjustable working depth so that by the .first pair of rolls a circumferential nick beginning adjacent the front end of the block is cut into the material of the hollow block, which nick is gradually widened by the following pairs of rolls toward said end. The axes of said rolls are inclined to the on account of the inclined position of their axes, are arranged on the outer and inner periphery of the hollow block alon a helical ine and can thus come in wor 'ng engagement therewith in a successive way onl T he outer force, which pushes the hollow block into the working rolls, must therefore be so strong that it overcomes the resistance of the first pair of rolls to such an extent that the vhollow block comes into the working range of'the second pair of rolls for permitting the latterto partlcipate 1n the. action of advancing the hollow block and thereby avoiding any overload and breaking of the drivlng axle of the "first pair of rolls.

The present invention provides improvedv means for overcoming said difiiculty. According to the same, the work1ng rolls are extended in the direction of the incoming hollow block, that is toward their inlet end, and at these extensions made of such a working part of the rolls.

252,375, and in Germany February 25, 1927.

diameter that, in the position of the rolls required for the action of their .working parts, said inlet extensions engage the hollow block from its outside and from its inside and at the rotation of the rolls advance the same and introduce it into the Said inlet extensions of the rolls are so determined that the hollow block, as soon as it arrives at the same, is simultaneously caught by all the pairs of rolls. The advancing action of said roll extensions can be further increased by providing them each with one or more peripheral beads, which suitably have such a distance from the working part of the rolls and from each other as corresponds to the pitch of the helical line, along which the pairs of rolls are arranged about the inner and outer periphery of the hollow block.

Furthermore, the block advancing action of the rolls can still be increased by extending the rolls also beyond their working parts toward the outlet end thereof and so determining the diameters of saidwoutlet extensions that the hollow block drawn out p to form the tube is engaged from outside and from inside by said outlet extensions.

The improved construction of the rolls with an extension at their outlet end permitsalso to overcome the danger of the piece of material, thatis separated from the hollow block, by the nick produced by the first pair of rolls, being first turned over, instead of being directly drawn out, by the action of the following .pairs of rolls, which may occur particularly with a rather short length of said piece of material and with a rather deep nick produced. Said turnedover piece of material is then, of-course, firmly 'rolled upon the other material of the hollow block while the same is being drawn out by the action of the working rolls, but it produces dangerous flawsin the walls of the'tube which are thereby weakened at these places.

' By providing, according to the invention,

the roll with an incline or abutment behind its main deforming part with a cavity between both, that is, between said abutment main deforming part of the rolls, B the exand said main deforming part, said drawback last mentioned is easily overcome by the separated piece of material to be drawn out bearing then against said cavity and being prevented from turning over.

The accompanying drawing illustrates how the invention can be put into practice.

Fi 1 and 2 show, for a clear understan 'ng of the distinction between the known art and the invention, two different pairs of working rolls hitherto used, while Figs. 3 and 4 illustrate the improved arrangement for putting the invention into practice.

The reference letters designate: A the tension toward the inlet en'dthereof, C the extension toward the outlet end thereof, D the hollow block, E the incline or abutment behind the main deforming part of the rolls, and F a bead on the inlet extension B of the roll.

What I claim, is:

1. In a method of rolling tubes from hollow blocks consisting in drawing-out the latter in substantially axial direction by the utilization of pairs of rolls acting both from inside and outside upon said block and of which the axes are inclined to the axis of the latter, engaging the hollow block by inlet extensions of saidvrolls prior to the.

main working parts of the latter acting thereon thereby advancin the block and introducing it into the mam working parts of the rolls.

2. In a method as specified in claim 1, en-

gaging the hollow block by outlet extensions of said rolls after the action of the main working parts of the latter thereon, thereby increasing the advancing action of the rolls.

3. In a method as specified in claim 1, preventing the piece of material, that is separated from the hollow block at the beginning of the rolling action, being turned over and rolled upon the other material.

4. In an apparatus for rollingtubes from hollow blocks, the combination with a roll having a main deforming part, of an extension on at least one end thereof engaging the hollow block during the rolling'action of said main deforming part, said roll hav ing at least one peripheral bead on an extension of said roll at the inlet end thereof.

5. In a construction as specified in claim 4, an incline or abutment behind the main working part of said roll with a cavity between said abutment and said main working part. i

In testimony whereof I have hereunto set my hand.

f MARTIN ROECKNER. 

